Nowadays, it is a matter of course that vehicles make use of the restraint devices of vehicle occupant safety systems in order to protect the occupants from the consequences of accidents to the greatest extent possible.
This is achieved, for example, through the use of airbags installed in various places such as the steering wheel, the dashboard or on the sides of the vehicle. Furthermore, belt tensioners are being installed in the seatbelt systems more and more often, these belt tensioners limiting the forward movement of the vehicle occupant in case of an accident. It is also a known procedure to use so-called pre-crash sensors that already initiate a reversible tensioning of the seatbelt prior to a potential accident. In order to cushion the vehicle occupant more gently, belt force limiters are used that, beyond a certain force threshold, allow the seatbelt to be extended to a limited degree.
To the extent possible, the restraint systems are not adapted to an average vehicle occupant but rather, to the actual vehicle occupant. For this purpose, e.g., the unfolding depth of an airbag, its inflation hardness or the force threshold of the belt force limiter can be specified as a function of the weight, the sitting position or even the momentary position of the occupant in the vehicle. The detection of such occupant-related parameters should, of course, be as simple as possible in order to keep the associated costs to a minimum.